Device drivers typically use ACPI _HIDs/_CIDs listed in struct device_driver acpi_match_table to match devices. However, for generic drivers, we do not want to list _HID for all supported devices, and some device classes do not have _CID (e.g. SATA, USB). Instead, we can leverage ACPI _CLS, which specifies PCI-defined class code (i.e. base-class, subclass and programming interface). This patch adds support for matching ACPI devices using the _CLS method. Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx> --- drivers/acpi/scan.c | 75 +++++++++++++++++++++++++++++++++++++++-- include/acpi/acnames.h | 1 + include/linux/acpi.h | 10 ++++++ include/linux/device.h | 1 + include/linux/mod_devicetable.h | 6 ++++ 5 files changed, 90 insertions(+), 3 deletions(-) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index dc4d896..0579395 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -987,13 +987,82 @@ static bool acpi_of_driver_match_device(struct device *dev, bool acpi_driver_match_device(struct device *dev, const struct device_driver *drv) { - if (!drv->acpi_match_table) - return acpi_of_driver_match_device(dev, drv); + bool ret = false; - return !!acpi_match_device(drv->acpi_match_table, dev); + if (drv->acpi_match_table) + ret = !!acpi_match_device(drv->acpi_match_table, dev); + + /* Next, try to match with special "PRP0001" _HID */ + if (!ret && drv->of_match_table) + ret = acpi_of_driver_match_device(dev, drv); + + /* Next, try to match with PCI-defined class-code */ + if (!ret && drv->acpi_match_cls) + ret = acpi_match_device_cls(drv->acpi_match_cls, dev); + + return ret; } EXPORT_SYMBOL_GPL(acpi_driver_match_device); +/** + * acpi_match_device_cls - Match a struct device against a ACPI _CLS method + * @dev_cls: A pointer to struct acpi_device_cls object to match against. + * @dev: The ACPI device structure to match. + * + * Check if @dev has a valid ACPI and _CLS handle. If there is a + * struct acpi_device_cls object for that handle, use that object to match + * against the given struct acpi_device_cls object. + * + * Return true on success or false on failure. + */ +bool acpi_match_device_cls(const struct acpi_device_cls *dev_cls, + const struct device *dev) +{ + acpi_status status; + union acpi_object *pkg; + struct acpi_device_cls cls; + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; + struct acpi_buffer format = { sizeof("NNN"), "NNN" }; + struct acpi_buffer state = { 0, NULL }; + struct acpi_device *adev = ACPI_COMPANION(dev); + + if (!adev || !adev->status.present || !dev_cls) + return false; + + status = acpi_evaluate_object(adev->handle, METHOD_NAME__CLS, + NULL, &buffer); + if (ACPI_FAILURE(status)) + return false; + + /** + * Note: + * ACPIv5.1 defines the package to contain 3 integers for + * Base-Class code, Sub-Class code, and Programming Interface code. + */ + pkg = buffer.pointer; + if (!pkg || + (pkg->type != ACPI_TYPE_PACKAGE) || + (pkg->package.count != 3)) { + dev_dbg(&adev->dev, "Invalid _CLS data\n"); + goto out; + } + + state.length = sizeof(struct acpi_device_cls); + state.pointer = &cls; + + status = acpi_extract_package(pkg, &format, &state); + if (ACPI_FAILURE(status)) + goto out; + + return (dev_cls->base_class == cls.base_class && + dev_cls->sub_class == cls.sub_class && + dev_cls->prog_interface == cls.prog_interface); +out: + kfree(pkg); + return false; +} +EXPORT_SYMBOL_GPL(acpi_match_device_cls); + static void acpi_free_power_resources_lists(struct acpi_device *device) { int i; diff --git a/include/acpi/acnames.h b/include/acpi/acnames.h index 7461327..22332a6 100644 --- a/include/acpi/acnames.h +++ b/include/acpi/acnames.h @@ -51,6 +51,7 @@ #define METHOD_NAME__BBN "_BBN" #define METHOD_NAME__CBA "_CBA" #define METHOD_NAME__CID "_CID" +#define METHOD_NAME__CLS "_CLS" #define METHOD_NAME__CRS "_CRS" #define METHOD_NAME__DDN "_DDN" #define METHOD_NAME__HID "_HID" diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 536991b..9a01d5d 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -442,6 +442,10 @@ const struct acpi_device_id *acpi_match_device(const struct acpi_device_id *ids, extern bool acpi_driver_match_device(struct device *dev, const struct device_driver *drv); + +bool acpi_match_device_cls(const struct acpi_device_cls *dev_cls, + const struct device *dev); + int acpi_device_uevent_modalias(struct device *, struct kobj_uevent_env *); int acpi_device_modalias(struct device *, char *, int); void acpi_walk_dep_device_list(acpi_handle handle); @@ -542,6 +546,12 @@ static inline const struct acpi_device_id *acpi_match_device( return NULL; } +static inline bool acpi_match_device_cls(const struct acpi_device_cls *dev_cls, + const struct device *dev) +{ + return false; +} + static inline bool acpi_driver_match_device(struct device *dev, const struct device_driver *drv) { diff --git a/include/linux/device.h b/include/linux/device.h index fb50673..8e259c5c 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -237,6 +237,7 @@ struct device_driver { const struct of_device_id *of_match_table; const struct acpi_device_id *acpi_match_table; + const struct acpi_device_cls *acpi_match_cls; int (*probe) (struct device *dev); int (*remove) (struct device *dev); diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h index 745def8..cf0e0d198 100644 --- a/include/linux/mod_devicetable.h +++ b/include/linux/mod_devicetable.h @@ -191,6 +191,12 @@ struct acpi_device_id { kernel_ulong_t driver_data; }; +struct acpi_device_cls { + kernel_ulong_t base_class; + kernel_ulong_t sub_class; + kernel_ulong_t prog_interface; +}; + #define PNP_ID_LEN 8 #define PNP_MAX_DEVICES 8 -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html